1. FIELD OF THE INVENTION
The present invention relates to a video signal recording apparatus for recording a video signal with wideband, such as VTRs (Video Tape Recorders) applicable to EDTVs (Edited Definition Television), HDTVs (High Definition Television) or MUSE (Multiple Sub-Nyquist Sampling Encoding), which have been developed in Japan.
2. DESCRIPTION OF THE BACKGROUND ART
For apparatuses for recording a video signal with widebrand, such as HDTVs in Japan, it is known in the art that in recording the video signal, the video signal is arranged to undergo time base extension processing and to be divided into two channels to record (see for example, Japanese Laid-Open Patent Applications 62-196985 and 62-190981). When recordings are made in this manner, for example, with respect to an input video signal with a bandwidth of 8 MHz, an occupied bandwidth required is lessened to 4 MHz, one-half of 8 MHz, by conducting double time base extension of the input signal.
However, since the time base extension is doubled, time deviations will be produced unless the signal is divided into two channels. This recording method is thus adopted in the case where there is little room for bandwidth in a recording-reproduction system.
In a recording apparatus wherein the above method is adopted, however, there are often presented problems related to a difference of circuit characteristics caused by variations in two groups of circuit devices employed in the respective two channel systems.
More concretely, where there is a difference of circuit characteristics between two systems, a problem is presented in that adverse effects such as differences in brightness or color occur in every horizontal scanning period (1 line : 1 H) on a reproduced picture, thereby making a picture image on the screen much less clear.